Low Power Intermittent Messaging for Hearing Assistance Devices

1. A system, comprising: a first hearing assistance device configured to be worn by a wearer, the first hearing assistance device including: a receiver including a first clock having a first frequency drift, the receiver configured to receive on sleep intervals using the first clock as a timer; and a second hearing assistance device configured to be worn by the wearer, the second hearing assistance device including: a transmitter including a second clock having a second frequency drift, the transmitter configured to transmit at a time which is a multiple of the sleep intervals using the second clock as a timer, wherein the transmitter is configured to transmit a repetition of packets having a length that increases with a time between transmissions based on one or more of the first and second frequency drifts, the length selected to ensure detection of the packets by the receiver regardless of drift of the first and second clocks.

2. The system of claim 1 , wherein the transmitter is configured to transmit the repetition of packets for a duration that increases with a time between successful resynchronization events.

3. The system of claim 2 , wherein the duration is based on one of a first and second clock frequency drift percentages.

4. The system of claim 2 , wherein the duration is selected to ensure detection of the packet by the receiver regardless of drift of the first and second clocks.

5. The system of claim 1 , wherein the repetition of packets contains a sequence number to prevent the receiver from acting multiple times on data contained in a packet of the repetition of packets.

6. The system of claim 1 , wherein the receiver is adapted to change channel of reception when signals are received but a packet is not detected.

7. The system of claim 1 , wherein at least one of the first hearing assistance device and the second hearing assistance device include a hearing aid.

8. The system of claim 7 , wherein the hearing aid includes a behind-the-ear (BTE) hearing aid.

9. The system of claim 7 , wherein the hearing aid includes an in-the-ear (ITE) hearing aid.

10. The system of claim 7 , wherein the hearing aid includes an in-the-canal (ITC) hearing aid.

11. The system of claim 7 , wherein the hearing aid includes a completely-in-the-canal (CIC) hearing aid.

12. The system of claim 7 , wherein the hearing aid includes a receiver-in-the-canal (RIC) hearing aid.

13. The system of claim 7 , wherein the hearing aid includes a receiver-in-the-ear (RITE) hearing aid.

14. A method, comprising: synchronizing a first clock of a transmitter of a first hearing assistance device configured to be worn in a first ear of a wearer with a second clock of a receiver of a second hearing assistance device configured to be worn in a second ear of the wearer at a synchronization time; determining a time interval between the synchronization time and a transmission time of a transmission; calculating a drift window using a potential drift amount between the first clock and the second clock over the time interval; transmitting the transmission with the transmitter, the transmission including a repetition of packets having a duration based on the drift window; and receiving with the receiver at a plurality of predetermined sleep intervals by activating the receiver for a duration of time of at least the drift window at each sleep interval to determine if a signal is present.

15. The method of claim 14 , wherein at least one of the first hearing assistance device and the second hearing assistance device include a hearing aid.

16. The method of claim 14 , comprising: if a signal is present and not recognized in a predetermined time, then changing to a new receive channel.

17. The method of claim 14 , wherein the transmission includes a repetition of packets that is approximately continuous.

18. The method of claim 17 , comprising: if a signal is present, then receiving packets with the receiver until no packets are received for a predetermined time.

19. The method of claim 14 , wherein the transmitter sends the repetition of packets upon detection of an event, the repetition of packets including a duration related to the drift window.

20. The method of claim 14 , wherein the first clock and the second clock are synchronized upon a successful receipt of the transmission.